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Livestock Waste
What is "Composting" ?
Composting is not a new waste treatment technology. It has been widely practiced by gardeners and farmers all over the world as a sustainable means of returning nutrients to the soil. The process of composting transforms organic waste such as livestock waste into useful soil conditioner or fertilizer. As compost is stable and readily assimilated by soil, it can enhance soil structure and help prevent soil erosion. As the crop agriculture industry in Hong Kong is small, the potential uses of compost are mainly for landscaping, golf course and race course maintenance, and horticulture industry. Some compost products have established brand names and compost in small packages is also available in the retail market.
Location of Sha Ling Livestock Waste Composting Plant (SLCP) and Animal Waste Composting Plant (AWCP)
Please click the spot for information of SLCP and AWCP
Map of Hong Kong
SLCP is located at Sheung Shui, New Territories, Hong Kong.
AWCP is located at Yuen Long, New Territories, Hong Kong.
Sha Ling Livestock Waste Composting Plant
Background information
To combat pollution from the discharge of untreated livestock waste to watercourses, EPD introduced the Livestock Waste Control Scheme in 1987 and amended it in 1994. This Control Scheme bans livestock keeping in those areas designated as Prohibition Areas. Livestock keepers operating in other areas can continue to rear livestock provided that they handle the waste properly and treat it to the required effluent standards before discharge. Water pollution caused by livestock waste has been substantially reduced since the Control Scheme became effective.
To assist the livestock farmers in disposing of livestock waste in an environmentally acceptable manner, the government provides them with:
- Technical assistance by publishing Code of Practice and guidance notes on waste treatment options and setting up demonstration treatment plant in private farms
- Financial assistance in the form of capital grant for installation of waste treatment facilities
- A free livestock waste collection service
With regard to the livestock waste collection service, EPD has appointed a contractor to provide waste collection bins free to the livestock farmers in need of the collection service and collect the livestock waste from the farms on a regular basis. The contractor delivers the livestock waste collected to the Sha Ling Composting Plant (SLCP) for composting. Since the amount of livestock waste collected exceeds SLCP's intake capacity, the surplus livestock waste is delivered direct to landfills for disposal. If you want to know more information about the Livestock Waste Control Scheme, click here.
Operation Details
The contractor provides leak-proof collection bins to livestock farmers for containing livestock waste generated from their farms. Livestock waste is collected by the contractor's collection vehicles on a regular basis. Part of the livestock waste is delivered to SLCP for composting and the remaining is disposed of at landfill sites. On arriving SLCP, the livestock waste is mixed with shredded wooden pallets. The mixed material is placed within fermentation box up to a height of 2.5 metres. Air is blown through the material by air pipes that are laid in the concrete floor of the fermentation box. Within a period of 6-8 weeks, fermentation is completed and the semi-matured compost is transported to maturation shed for further maturation. When matured, the compost is sold as soil conditioner and the quality of the compost is monitored by testing conducted on the compost samples.
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[Image of Livestock Waste Collection]
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[Image of Use of Shredded Wooden Pallets as Mixing Pallets]
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Livestock Waste Collection
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Use of Shredded Wooden Pallets as Bulking Agents
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[Mixing of Shredded Wooden Pallets and Pig Waste]
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[Compost at Fermentation Boxes]
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Mixing of Shredded Wooden Pallets and Pig Waste
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Compost at Fermentation Box
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[Compost at Fermentation Boxes]
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[Image of Compost at Maturation Shed]
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Compost at Fermentation Boxes
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Compost at Maturation Shed
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Animal Waste Composting Plant
Background information
The Animal Waste Composting Plant (AWCP) is specially designed by using in-vessel composting technology which turned the horse stable waste generated during the 2008 Olympic and Paralympic Equestrian Events in Hong Kong into useful compost. It has a design capacity to treat around 20 tonnes of horse stable waste every day, comprising horse manure, straw or paper bedding materials, and horse feed etc. These wastes are rich in organic content and can be converted through a composting process into useful organic compost suitable for landscaping, horticultural and agricultural uses. The AWCP is currently undergoing trial composting of other tyres of organic wastes.
AWCP is located at Ngau Tam Mei in the Yuen Long District. The project manager is Electrical and Mechanical Services Department.
In-vessel Composting
In-vessel composting occurs within a fully enclosed vessel. This enables better control of moisture content and temperature during the treatment process.
In-vessel composting also enables:
- Production of a more consistent quality compost
- Reduced use of bulking agent
- Better odour control as potentially odorous air from the process can be easily collected for treatment
- Smaller footprint as compared with other composting methods
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Rotary in-vessel composter
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Operation Details
Collection trucks deliver the horse stable waste to the AWCP and unloaded at the pre-treatment plant. Here, the unloaded waste is tested for moisture content. Waste is then fed into a hopper and is conveyed through a ferrous magnet separator, a non-ferrous metal separator and a disc screen where metals, non-ferrous materials and plastics in waste are removed. Waste is further mixed by a mixer before feeding by conveyors into in-vessel composters for composting around 3-4 days. Odour that may be arising from the process is eliminated by contact de-odourizer. The semi-matured compost is transferred into bunkers for curing about 42 – 45 days. After curing, quality of the mature compost is tested before it is marketed.
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Pre-treatment building where waste is received and pre-treated
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Pre-treatment process for feedstock preparation
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Rotary in-vessel composter where bio-degradation takes place
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Bunkers for compost maturation
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Deodorisation system using Bio-filters
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Raw horse stable waste
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Compost after 33 days
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